Coated welding electrode



1934- H. R. PENNINGTON 7 1,972,067

' COATED WELDING ELECTRODE I I Filed June ,16, 1935 J0 J Z1.

Patented 3;,

non 1 a steel e Wire Comneny, Me, n,

e cornorshon of lln deletion done it,

lit is the object of 1 invention to provide e costed wel electrode which es possible welds oi high tensile s w-"1'- and high ductility and substantially free from inclusions of oxides d and nitrides and from gee holes and slag pockets; and which will permit as high rate of deposition and ot the some time give such depth of fusion t s weld deposit of proper contour is obtained.

in accomplishing this result, I include in the is costing, in addition to any desired orususl fluxsnd/or sles-io ingredients, a tail: tisl quantity of n arable scecis), :I-i

- cient so that it forms at least 8% of the total, and desirably between 10% to thereof, and

d5 pesibly es high as so% to 75% thereof especi in thin costings. The coo may be either a thick costing or a con, and is applicable both tor positive-connected electrodes sud negative=connected electrodes.

The acacia serves s nr of functions:

1. On be raised to the tempereture incident to wel, it burns to produce oxides of carbon, probably both carbon monoxide and carbon dioxide; which serve to shield the arc, and the weld 25 which is being formed from contact with the air and from the inclusion of oxides and nitrides so well es from oxidation. This is of course more pronounced in thick costings, but exists to an appreciable extent in thin coatings.

2. It holds its solid form, with substantially no melting, up to the tempersturewhere it burns to form carbon oxides; and thus serves to hold the coating in piece substantially down to the point where the electrode wire is melting into as the are, and in thick coatings us even somewhet beyond that so that the ore is kept within so: inverted croter formed by the pro shell of -supnorted coating.

s. in itself it serves as a binder, both when the so electrode is hot end when it is cold, and essists the action of other binder present. In doing this the srabic may to s sort of costingsupporting honeycomb shell or matrix; by being e lved in water or in a solution of sodium sili- 5 cote or noum silicate to e the costing paste, and being deposited from mich solution on eyenorshon of water.

l. It serves es s. friction-deer when paste is used to to the flux coating, and facilitates-exso oi the posts when cos is'anplied by con.

The eccom m; .rs shows it coeted rod H ns-=- intio s. l is on eletion oi as coeted wells rod; wd in: 2 is's so. thereof, on the lme 2-22 oi l.

The following are epl Emmple i executors Ingredients by weighs Percent Gum amhio 15 Sodium silicate (liquid) 25 Ferromsnganesal0 Silica flour 10 Magnesium silicate (such as talc) 10 Aluminum silicate (such as kaolin). 30

The solid ingredients, desirably in powdered form, are suitably mixed in dry form, and then mixed thoroughly into the liquid sodium silicate. Some water may be added, it desired, to obtain a thinner consistency, althoughthis is wholly optional; for it is desirable that the i be of such consistency that it may be extruded through dim in a known manner to form a, coating sleeve about the welding-rod wire, although the coating may also be applied in other ways, such as dippin The sodium silicate added may be in solid form, if desired, but in that case water is added to m duce a solution. The sum arsbic may be added 80 either as a. solid orin water solution, for it is very soluble. The thickness of the coating 11;:

very, but with this type of coating it usually does not exceed 1/32 of an inch for a wire of 3/ 16 inch diameter. a commonly used size for welding rods.

Example .2

Percentage Ingredients by wt These are mixed and applied in the same we? as that outlined in Example in either of msmples l and 2, o is the oxide end silica flour, .1

wil

able proportions to form aluminum silicate, may be substituted for the kaolin; and/or in Example l a mixture of magnesium oxide and silica. flour, desirably in the same proportions as they exist in talc, may be substituted'for the talc. I include such mixtures in the terms aluminum silicate and magnesium silicate respectively.

desirably specular hematite, although that is not necessary. Ordinary red hematite or red iron oxide may be used.

Ferromanganese is always a desirable ingredient in coating compositions. However, it is not an essential one; and it may be omitted in some instances, or it may be replaced in part or in whole by other compounds of manganese, desirably those which also contain some iron, such for instance as silicomanganese or ferrosilicon. These are all iron-manganese alloys.

The silica flour and/or the sodium silicate which are given in all three examples may be increased or diminished in amount, and the silica flour may even be omitted, as desired; for they serve to adjust the basicity of the slag which is obtained when the coated rod is used, and may be increased or decreased in amount as it is desired to decrease or increase respectively the basicity of the slag.

The liquid sodium silicate may be ordinary water-glass, which usually contains about 60% water. It may vary somewhat in the proportion of silica to sodium; and the amount of silica flour added depends somewhat on the composition of the liquid sodium silicate as well as on the amount of the sodium-silicate used. As has already been stated, sodium silicate in dry form may be used; and suflicient water is then added to make a paste of the desired consistency. Other alkali-metal silicates, such as potassium silicate, may be used in place of sodium silicate. Such alkali-metal silicates and gum arabic may be used together in many other coating mixtures besides those given in the examples. l

The gum arabic is dissolved either in the sodium silicate or in water, to permeate the whole mass of paste. When the paste is dried and baked, as is done after the rod is coated with the paste, it loses water, and deposits the dissolved gum arabic through the coating in the form 01' a honeycomb shell or matrix which adds materially to the physical strength of the coating.

Although in all three of the examples given above I have used sodium silicate and ferromanganese and silica flour, my invention is in no way limited in its broader aspects to coatings which contain these ingredients in addition to the gum arabic. The examples given above are especially desirable where the coatings are the so-called thick coatings; although they'can be used even when the coatings are only a few thousandths of an inch thick. However, for thin coatings, having a thickness of the order of a few thousandths of an inch, I prefer to use mixtures which do not include sodium silicate or silica flour or ferromanganese; but which still use the gum arabic for its advantageous properties.

Example 4 One example of a coating which is especially suited for thin coatingsis that which is shown in the co-pending application of Paul R. Judy and myself, Serial No. 678,615, filed July 1, 1933, which has the following composition:

Titanium dioxide 8 to 12 ounces. Gum arabic 4 to 12 ounces. Water 1 gallon.

Example 5 Another example which is especially suitable for thin coatings is:

Parts by weight Calcium carbonate 20 Gum arabic 5 Water 20 The gum arabic is dissolved in the water, and thecalcium carbonate is suspended in the solution of gum arabic. This suspension and solution is suitably applied to the rod, and dried; leaving a deposit of gum arabic which not only holds the calcium carbonate in place on the rod but also has the other advantageous properties of gum arabic.

- Example 6 Another example, especially adapted for thin coatings, involves the use of at least 8 or 10% 120 of gum arabic with compounds of strontium, cerium, and/or barium, when they are used as co-ordinators or stabilizers in welding-rod coatings which may also contain sodium silicate. The provision of strontium, cerium, and/or barium in welding-rod coatings is the invention of Paul R. Judy, and is-included in the subject-matter of his application Serial No. 678,616, filed July 1, 1933, assigned to the same assignee as is my present application; and is given here merely as an example in which use may be made of gum arabic in substantial quantity in the coating.

I claim as my invention:

1. A welding rod having a flux coating of which gum arabic forms at least 8%.

2. A welding rod having a flux coating comprising gum arabic and one or more fluxing ingredients, with the gum arabic forming at least 8% of the whole.

3. A welding-rod having a flux coating comprising gum arabic and one or more slag-forming ingredients, with the gum arabic forming at least 8% of the whole.

4. A welding rod having a flux coating including at least 8% gum'arabic ,and water-soluble sodium silicate.

5. A welding rod having a flux coating including at least 8% gum arabic and a water-soluble alkali-metal silicate. I

6. A flux-coated welding rod, the coating 01' 150 which includes at least 8% sum arabic, a watersoluble alkali-metal silicate, and an iron-manganese alloy.

'1. A flux coated welding rod, the coating of which includes at least 8% sum arabic, a watersoluble alkali-metal silicate, an iron-manganese alloy, and aluminum silicate.

8. A flux coated welding rod, the coating or 

